1. Field of Invention
This invention relates to the field of medical apparatus, particularly to a medical device for immobilizing a patient's head during treatment or examination by tomographic or X-ray apparatus or the like. Also the head immobilizer of the invention can be used to position a patient's head in any precise position, identical to a previously-held position.
2. Description of Prior Art
During certain medical treatments and examinations of a patient, his or her head must be held in a fixed, rigid position. Specifically the head, or another part of a patient's anatomy, must be held very rigidly during the following exemplary types of procedures: surgical procedures, including dentistry, emergency medical care, physical and occupational therapy, tomographic examinations (multiple X-rays taken using a CAT (computer axial tomography) scanner, NMR (nuclear magnetic resonance) tomographic scanner examinations ("pictures" taken in a similar fashion), X-ray malignancy treatment procedures (radiation beams directed at a focus in the body from a plurality of angles), etc. This is because tomographic and similar processes involve patient irradiations or the taking of multiple pictures from many angles over a period of time, usually a few minutes, to enable a computer to provide a composite cross section of the head. If the head (or other anatomical part) is allowed to move during the process, the resultant cross-sectional picture will be distorted and blurred and of little medical value.
Heretofore various methods and devices were used to immobilize the head for these processes.
In some, the head was cradled in a form-fitting rest. However such cradles or rests left much to be desired since they did not hold the head rigidly and thus the patient could easily move it during the process.
In others, the head was clamped, either from top to bottom, side to side, in the mouth, or with a combination of these methods. While such clamps could immobilize the head, they were usually extremely uncomfortable for the patient since force from the clamps, when applied for an extended period of time, caused trauma to the patient. If the clamps were padded sufficiently to avoid trauma, they then were too resilient to hold the patient rigidly.
In still others, a clamping device was actually screwed into the patient's head, usually the cheekbones, under surgical anaesthesia. While this device held the patient's head in a very immobile manner, patients obviously found it extremely traumatic, painful, disfiguring, and uncomfortable.
In a further device, the patient was held by an air-impedance sheet draped over the patient's torso, which sheet was held in position against the patient by a vacuum source in communication with the underside of the sheet. This device did not fully immobilize the patient and also it was not feasible to use it to hold a patient's head because the sheet would block the patient's nose or mouth.
In addition to their foregoing disadvantages, most of the aforementioned devices also suffered from a lack of position repeatability. I.e., if the physician desired to reposition the patient in precisely the same position as previously used for a repeat treatment or diagnosis, e.g., for checking the patient's progress after treatment or for repeating a therapeutic treatment, most of the aforementioned devices could not be used to reposition the patient in precisely the same position in which he or she was previously held.
In addition to holding the head for medical procedures, other applications exist where the body or parts thereof must be held rigidly or immobile without discomfort or trauma. E.g., in land, sea, air, or space vehicles, the head and/or the body must be held securely during positive and negative accelerations, e.g., when starting, stopping, in case of crashes, etc.